Example embodiments of the inventive concepts relate to a memory device, a memory controller, and/or a storage device including the memory device and the memory controller. For example, at least some example embodiments relate to a method of operating a memory device to read data, a method of controlling a memory controller, and/or a storage device including the memory device and the memory controller.
Semiconductor memory devices may be divided into volatile memory devices which lose data stored therein when the power supply is turned off and nonvolatile memory devices which do not lose data stored therein. Volatile semiconductor memory devices may have fast read and write speeds, but content stored therein may be lost when an external power supply is cut off. On the other hand, nonvolatile memory devices may be slower in reading and writing compared with the volatile semiconductor memory device, but may retain the content therein even when the external power supply is cut off.
In a flash memory device, as an example of a nonvolatile memory device among semiconductor memory devices, it may be desirable to more precisely form threshold voltage distributions of memory cells included in the flash memory device as the number of bits of data stored in one memory cell increases. For example, when the threshold voltage distribution is formed at a position different from a predicted position, a problem such as a reading error may occur.